Does thermal biology differ between two colour pattern morphs of a widespread Australian lizard?

Area of Science:

• Ecology
• Evolutionary Biology
• Herpetology

Background:

• Phenotypic variation allows species to adapt to diverse environmental conditions.
• Color polymorphism in lizards, like the delicate skink (Lampropholis delicata), can correlate with geographic and climatic variables.
• Morph frequencies in Lampropholis delicata vary latitudinally and by sex, suggesting potential adaptive significance.

Purpose of the Study:

• To investigate if thermal biology differs between the plain and striped color morphs of the delicate skink, Lampropholis delicata.
• To determine if observed differences in heat exchange rates between morphs are adaptive and linked to their distribution.
• To explore the role of behavioral thermoregulation in maintaining body temperature across morphs.

Main Methods:

• Comparative analysis of heating and cooling rates, sprint speed, thermal preference, field body temperature, and metabolic rate.
• Testing was conducted on both plain and striped morphs of Lampropholis delicata, considering sex differences.
• Morph frequency data across latitudes were analyzed in relation to thermal traits.

Main Results:

• Plain morph individuals exhibited faster heating rates compared to striped morphs.
• No significant differences were found in other thermal traits, including cooling rates, thermal preference, field body temperature, and metabolic rate, between the morphs.
• Coloration in Lampropholis delicata influences heat exchange dynamics but does not appear to be the primary driver of adaptive thermal specialization.

Conclusions:

• While color affects heat exchange rates in Lampropholis delicata, behavioral thermoregulation appears to equalize body temperatures in the field.
• The observed color morph distribution is unlikely driven solely by thermal selection pressures.
• Other environmental factors or selection pressures may be responsible for the latitudinal variation in delicate skink color morphs.